Thiamine should be taken at least 200mg/day. Up to 300mg if necessary.
This vitamin may be depleted by certain drugs (diuretics,antibiotics)
and some people have errors of metabolism involving thiamine.
It specifically helps with burning type pain. You should know if it is working for you in about a month...but you may need it longer.

Omega-3 encompasses Alpha linolenic acid (from Flax, and some nuts) and also fish oil. Alpha Linolenic acid is converted to long chain Omega-3s called EPA and DHA in the body, from primary Alpha linolenic acid. So using the term Omega-3 can be confusing. I assume you mean fish oil, and in that case any will do.
All are carefully made and have shown no contamination by heavy metals.
We use an enteric coated double strength one from Costco and Sam's club. Two doubles or 3 regular is a good place to start dose wise.
These are very reasonably priced. If you have low intake of Omega-3 foods then using fish oil supplements is necessary. I have a thread on this in the Vitamin forum. It is listed in the stickies.
B6 and magnesium are needed to convert Flax oil to EPA and DHA.
Some people buy brand name Fish oil. Fisol is one, (enteric coated) or Nordic Naturals and Carlson's are both good. Dr. Sear's makes one too.
If you are just starting, you might like the enteric coated ones better, as beginner's often get fishy burps (repeating). This goes away with improved EFA status.

If you choose to avoid fish oil and only take flax, then some evening primrose is helpful to enhance conversion. The EPA portion of the long chain EFAs is the anti-inflammatory part. The DHA is more for the brain/depression, etc.

Take the oils with food for best absorption. Just about everyone has improvements with time. After a few months, you will be amazed.
Your skin and hair will improve, you may see a great reduction in GERD symptoms, improvements in asthma, less bronchitis, less depression, fewer colds, improved circulation, lower triglycerides, and much more. Your nervous system will be able to repair itself in general as well.

Neither need be expensive, as well.